Process of producing and finishing gears and other carbonized-steel parts.



UNITED STATES" PATENT OFFICE- James F. SALLOWS, or xannrmzoo, mrcnmnn.

rnoorss or rnonuomo mp, rxmsnme GEARS 4m) OTHER CARBONiZEb-STEEL PARTS.1

No Drawing,

' the following is a specification.

The purpose of this invention is to pro ride an improved process forproducing lnu'dcned steel or carbonized iron parts, such as gears andthe like, for avoiding deformation in the process of hardening. Itconsists in the several steps hereinafter de-' scribed, as set out inthe claim.

Heretofore difficulty has been experlenced in producing SSlJISfKClZOIysteel or carbonized iron parts requiring accuracy of dimen sion and termWithout grinding as the final process of finishing to form and forremoving scale, because the usual steps of harden ing produce not onlyinternal stresses but also deformation, and too1-finishing cannotheresorted to after the hardening is com plotted, and the deformationscan be c0r reeted only by a process which can be no plied to thehardened material, such, forex' ample, as the process of grinding andpolishl have overcome this difficulty by the fol lowing process:

I first produce by forging the article desired in the. rough, or ofapproximately the form and dimension required. I next rough-n'1achinethe part to astill closer approximation to the form and dimensionrequirecl'. For the third step I case-harden the part, employing theusual means and processes for carbonizing -it quite deeply, and upon theconclusion of the carbonizing step, I quench the parts in oil firstallowing them to cool in the pots to proper tem- Specification 0;Letters Patent. at nt t, 2,1 application llled Ileceinber 7, 1917.Serial No. 205,978.

peratu're for'hardening by the quenching As the next step, I box thepart in carbon dust, that is, inclose it in a box and pack it withcarbon dust, and heat the package to proper temperature for annealing,that is to say, about 1400 degrees 1 and permit it to remain in. theheating furnace a proper length of time t produce the desired refinedstructure of the casing, and then remove the package from the furnaceand allow to cool in the atmosphere, or normally, without unboxi ng'.

The next step consists in finish-machining the part to final form.

I then repacli in carbon in a box, and reheat to a temperature of 1200to 1400 degrees F., and remove from the packing and quench the articlein oil or wateraceording to the grade of steel required.

The ,parts produced in this manner are found to have the form anddimensions to which they are finish-machined, without warping ordistortion ofany sort, and ap-.

pare'ntly without injurious internal stresses.-

The process of producing steelor carbonized irbn parts comprising thefollowing steps: first, rough-forming the parts; second, rough-nmchiningparts approximately to the form and outline required; third, carbonizingdeeply by case hardening process, and quenching in oil; fourth,annealing by boxing in moderately insulating material as carbon dust,limiting and allowing to cool normally in the atmosphere withoutunboxing; fifth, finish-machining; sixth, re-boxing-in moderateinsulation,re-heating and quenching in oil or water according to thegrade of steel required.

In testimony whereof, -'I have hereunto set my hand at Kalamazoo,Michigan, this 30th day of-November, 1917; V

JAMES FQ-SALLOWS.

